Role of vitamin D on immune function
Although habitual use of vitamin and mineral supplement by athletes/sportspeople is not advised, the IOC consensus statement (2010) has drawn attention to the role of vitamin D. Vitamin D is essential for maintaining normal calcium metabolism, regulating muscle function and bone health. Few foods in the UK naturally provide vitamin D, and data from the latest Family Food Survey suggest that intakes of key vitamin D-rich foods, in particular, oil-rich fish, eggs and fortified margarines, are in decline and as such, the population is at risk of having vitamin D deficiency during the winter months. Inadequate status has been associated with an increased risk of chronic and auto-immune disease including car-diovascular
disease, diabetes, rheumatoid arthritis and certain types of cancer, as well as loss of bone mineral density (Defra 2008; Ruxton & Derbyshire 2008). Vitamin D has tended to be overlooked as a key concern in sports nutrition. However, it has recently come to the fore that vitamin D insufficiency (i.e. a serum concentration of 25(OH)D